Film 4 - color changed from clear to black/red depending on the thickness of the film. Thicker portions of the film were darker than thinner parts, which appeared red. The black parts of the film were very hard, while the thinner parts of the film were more flexible.

Film 5 - color changed from clear to black, film became harder/more brittle

Film 6 - color changed from clear to black, film became harder/more brittle

Film 7 - Film remained the same

Notes

The color change from clear to black is the result of the crosslinking that occurred in the presence of the acid.

Film 7 remained the same because a weak acid was added, not a strong acid.

The hot plate used to evaporate the excess water from the films made on Wednesday was too hot and thus, bubbling was observed in the films. We will remake the films on Monday.